Buckle assembly for tie down strap

ABSTRACT

A cam buckle frame includes a first roller aligned transversally across the frame proximate the free end of an operating lever of a web toothed locking cam. The roller directs the web in contact with the operating lever of the locking cam to provide a self-locking feature without requirement for a torsion spring. Other transverse posts and rollers may be included in the web clamp frame and the corresponding hook end of the tie-down to form a secured pulley arrangement to provide a multiplication of applied tension force. One end of the frame side-wall adjacent said first roller may form an integral hook assembly with a structural latch. An option is to have the frame closed out by connecting opposing walls with a section that provides a center port to allow attachment of various style hooks. A pivoting hook-end used to connect to soft hook loops is described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 12/930,959 filed Jan. 20, 2011 which is, in turn, a continuation-in-part of Ser. No. 12/802,845 filed on Jun. 15, 2010 which, in turn, obtains the benefit of the earlier filing date of U.S. Provisional Application Ser. No. 61/338,993 filed on Mar. 1, 2010 and the benefit of these earlier filing dates is claimed for all matter common therewith.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to improvements in web cam buckles such as are used in motorcycle transport tie-down restraints. The improvements herein described provide cam buckle tie-down with higher pre-load capacities. Also included are improvements in the design of associated web hooks for the tie-downs.

2. Background Art

The huge outdoor recreation industry in the United States has resulted in a requirement for transporting motorcycles and other RV vehicles.

Within this backdrop, the inventor hereof has devised several mechanisms that in one way or another assist in lifting and transporting a recreational device like a motorcycle or a personal watercraft as exemplified in the teachings of U.S. Pat. Nos. 4,790,713 and 4,932,829 that were issued to the inventor hereof, and in published U.S. Patent Application Publication No. 2005/0111945 also to the present inventor.

More recently there are described even further improvements in lifting mechanisms such as those disclosed in U.S. patent application Ser. No. 12/321,267 filed Sep. 2, 2008 for a truck bed carrier and U.S. patent application Ser. No. 12/384,630 filed Apr. 8, 2009 dealing with the confined lifting geometries associated with an enclosed carrying vehicle, both of which are incorporated by reference as if fully set out at length herein.

It is well appreciated that any extended transport of RV vehicles will require proper restraint of that cargo during transport.

The principal components in the restraint methods, are the wheel chocks to restrain horizontal movement, and the adjustable tie-down straps or cables used to limit vertical movement of the cargo. These tie-down restraints have two load requirements:

Maximum Working Load—this is the strength of mechanical components of the tie-down assembly reduced by a safety factor.

Preload—Is the static down force imposed on the transported vehicle by tie-downs. The preload tension desired will depend primarily on the weight of the restrained vehicle and the stiffness of the suspension system of said vehicle. The purpose of “preload” is to obtain sufficient down-force on the suspension to limit vertical movement of a vehicle during transport, but to not apply excess preload force which can damage the vehicle suspension system.

In the past years, simple cam buckle tie-downs have worked well for restraining lighter weight motorcycles. The simple cam buckle tie-downs are limited in the amount of preload force to what one normal person can pull. For that reason the preferred tie-down for heavy motorcycles has been the ratchet type where the higher restraining forces are obtained by winding up a flexible strap onto a ratcheted spool, as exemplified in the teachings of U.S. Pat. No. 7,416,167 issued to Knox, U.S. Pat. No. 6,547,218 issued to Landy, and many others. These ratchet type mechanisms are unwieldy in the cramped spaces of the cargo area of trucks and trailers. The light duty ratchets can only wind up a short amount of web material on the small spools; which results in lengthy adjustment time. Also when the high compression force in the transported vehicle's suspension system is released by the ratchet pawl, there can be a dangerous jump movement in the transported vehicle.

For these reasons, the convenience of a flexible strap with a cam buckle is often preferred over ratcheted types. However, the simple cam buckles are limited in the amount of preload force that can be imposed by one's arm in a cramped space. For that reason a cam buckle that developed additional force due to multiplication by internal pulleys would be a welcome solution to many recreational vehicle tie-down requirements.

The clamping buckles that are particularly adapted for these tie-down applications are cam buckles including a one piece frame exemplified by buckles sold under model designations 40880-22; 42195-11; or 40880-15 by Ancra International, LLC, Hawthorne, Calif. Cam buckles of this type typically include a generally C-sectioned unitary frame supporting a pivot extending between the lateral walls thereof on which a spring biased lever is pivoted to press a toothed cam against a strap or belt extending through the frame interior. Once grasped against the strap tension, the engagement of the cam is then released only by pressing the lever against its spring bias, thereby lifting the cam from its captured position against the strap.

It has been found that in the foregoing cam buckle structure the lateral walls of the single piece frame can be rendered even more useful to serve as supports for additional pivots about which the strap can be looped in order to obtain the load multiples of additional pulleys. Also by proper location of the primary pulley and the locking cam, the load strap is directed just under the actuating lever of the cam, so that tension in the web will provide a lifting force to the lever to initiate rotational closing of the web clamp. The shape of the clamp cam with directed teeth, then locks the load strap and prevents its release unless direct pressure is applied to actuating lever. This eliminates the need for an actuating spring.

Typical motorcycle tie-downs have heavy steel “S” open hooks at the ends to allow attachment between motorcycle and vehicle carrier. For modern motorcycles, the steel hooks (even with vinyl coatings), are not acceptable to the vehicle owner. For this reason, “soft hooks” are used for direct attachment to the cycle. These soft hooks are stitched nylon web loops that can be cinched to suitable motorcycle structure with a length adequate to keep the heavy hook and the adjacent steel web clamp a safe distance from the motorcycle during transport. The open hooks are trapped onto the restrained vehicle by the web tension. However, certain rough road conditions (dips, heaves, ruts, etc) and sudden carrier vehicle direction changes can create so much movement on the motorcycle suspension as to allow the standard open hooks to escape from the soft hook web loop. A new web clamp design that incorporated a hook in the design of the web clamp frame was described in the parent application hereof. This integral hook is described as having a closing latch to support the open side of hook, and of course the latch prevents the possibility of the hook escaping the loop of a soft hook.

Since “soft hooks” are a standard means to attach to street motorcycles, there is a need for optimum means to attach to these types of web loops. An alternate design specific for a web hook that will lend itself for use as web clamp end-attachment is also described herein.

The web clamp designs herein resulted in another consideration for motorcycle tie-down equipment. When motorcycles are transported inside trailers or trucks, the web clamps are frequently in a location that is access restricted. In this case, the direction orientation of the web clamp is critical in order to allow the operator to have a straight line pull on the web tensioning end of a tie-down. Also with the inventive force multiplying web clamp design, it is important to avoid misaligned or twisted webs on the tie-down, as the increased friction will limit the ability for the web clamp to develop the desired web tension. It is the accommodation of the new web clamp design that will insure optimum orientation of the web clamp for the operator, and proper alignment of the web with the web clamp. As used herein, the terms “web” and “strap” are interchangeable.

SUMMARY OF THE INVENTION

Accordingly, it is a general purpose and object of the present invention is to provide a single piece frame cam buckle assembly for multiple loop load application.

Further objects of the invention are to provide improved end-attachments for the cam-buckle frame to facilitate and improve the means to attach the web tensioning device to the transported vehicle.

As described in the parent application hereof, the single piece frame may be modified to extend as a longitudinal projection of one side-wall that is formed into a partial U-shape and aligned to form a hook opening between its free end and the opposing side-wall. This hook opening is then closable by a latch pivoted from the free end of the hook to the adjacent post. This latch serves to increase the load capacity of the hook, and to secure the tie-down to restrained cargo.

Briefly, these and other objects are accomplished within the present invention by providing a single piece frame of a cam buckle which includes a plurality of transverse pivot rollers bridging across the lateral walls of the frame. The pivot axis and the radial dimensions of the pulley ahead of the web clamp direct the web under the foot-pad of the clamp portion of the web clamp. The pivot axis and dimensions of the web clamp cam with its lever, are selected so that the ball-end of the lever arm is just resting on the surface of the web. As the web is pulled under the web clamp during tensioning by the operator, the cam is rotated so that the lever arm of the cam depresses the center of the span of the passing web. When the operator finishes a tension adjusting pull, the resulting tension on that web span lifts the end of lever which then engages the teeth of the cam. Once engaged to web, the web tension further rotates the cam to secure a lock on the web. The strap induced forces on the cam lever effectively replace the function of the torsion spring. The web clamp can only be released by depressing the operating lever to rotate the clamping cam. A rotatable cam interlock is positioned adjacent the levered cam, and can be manually rotated by one's thumb to provide a lock to prevent any accidental depression of the operating lever of the toothed clamping cam.

Those skilled in the art will appreciate that for the inventive cam-buckle to operate properly, it would require a close fit tolerance between the eccentric locking toothed cam and opposing base of the buckle assembly. The thicker web materials such as those having greater than 2.0 mm thickness, can have a large variation in web thickness from different manufacturing lots. Included herein is a description of a way to allow adjustment of this type of cam buckle for a particular web thickness.

An alternative design for an end-attachment web hook is described herein. This end attachment is a pivoting hook, designed specifically to securely capture the web loop of a soft hook. In one embodiment this attachment is dimensioned to be mated to the closed end of the single piece frame of the web clamp. This end attachment would be attached to the frame with a pivot pin and low friction washer. As an alternate to a fixed end web hook, a pivoting web hook end-attachment will pivot axially to allow the web clamp to be orientated as best suited for the operator. Typically this end attachment would be generally rectangular in shape with a narrow opening path sized to allow the soft hook loop to slip onto the attachment. Due to the narrow width of the slit, the only way that the loop web can be released is to hand guide the web through the slit.

Further, the axially pivoting end attachment can be incorporated into a web hook for capturing a web loop attached to cleats, or other hard points of the transporting vehicle. This will insure that the tensioning web cable is not twisted and is directly in line with the web clamp frame. It will be appreciated that this design is basically a U-channel shape frame where the opposing walls have pivot posts that can serve to install pulleys or serve as the termination post for the load web. The center of the frame is the pivot axis for attachment of a pivoting slotted hook. The pivot points of this frame allow multiple line load paths between the web clamp and this end hook.

BRIEF DESCRIPTION OF THE DRAWINGS

The aforementioned objects and advantages of the present invention, as well as additional objects and advantages thereof, will be more fully understood herein after as a result of a detailed description of a preferred embodiment when taken in conjunction with the following drawings in which:

FIG. 1 is a perspective illustration of a prior art cam buckle assembly deployed for use in cargo restraint;

FIGS. 2A and 2B are respective exploded end perspective illustrations of the inventive force multiplying cam buckle assembly having the integral hook in the buckle frame and showing the location for the post of the interlock cam;

FIG. 2C shows the same basic frame design illustrated in FIGS. 2A and 2B but without the locking toothed cam. This design can serve as a hook end of the web strap. This design includes the integrated hook and latch, and the post positions for a pulley for the force multiplying load paths;

FIG. 3 is a perspective illustration of the frame of the inventive cam buckle assembly with the buckle frame having a closed end, to accept the pivoting talon hook for attachment to a soft hook web loop;

FIG. 4 is a perspective illustration of the inventive cam buckle with a closed end frame with a pivoting talon hook. The opposite end of the web strap as depicted has a pivoting talon web hook that would attach to a web loop from the available cargo tie-down attach point in the vehicle. FIG. 4 also shows the pivot post which can serve as a terminal post or a pulley post for the web when configured for force multiplication;

FIGS. 5 and 6 are respective diagrammatic sectional views of the inventive cam buckle with pivoting web hook. The hook at the cam-buckle would be used to secure a web loop cinched to the transported vehicle. The pivoting hook assembly at end of the tie-down would be used to secure a web-loop from the cargo attach point in the transporting truck or trailer. FIGS. 5 and 6 also illustrate a pulley loop arrangement for two-line and three-line force multiplication; and

FIG. 7, comprising FIGS. 7A and 7B, provides a perspective illustration of a means to allow the base frame of buckle to be adjustable to accept different thickness web materials.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1 a conventional cam buckle assembly generally designated CB comprises a single piece unitary frame UF of a generally C-shaped section defined by a bottom surface BS spanning between two lateral walls WS1 and WS2. A transverse pivot pin PP extends between the walls WS1 and WS2 proximate the one ends thereof to support a cam piece assembly CP that has a lever actuating arm. The end of the lever arm is referred to as LE.

A helical bias spring SP on pin PP is compressed between wall WS1 and the lever LE. The spring urges the free end of the cam piece CP in the direction of arrow AA towards an anvil piece AN supported on the bottom surface BS, capturing a load carrying strap ST therebetween as it is passed through an aperture AP in the bottom surface BS against the tension force TF carried by the strap to an end hook HK. This force corresponds to the manually applied tensioning force at the strap's free end FE. A strap loop SL around the other portion of the bottom surface BS bordering the aperture AP is then useful as the other end of this tension force combination.

While there are many commercial forms of the foregoing cam buckle assembly, those skilled in the art will be familiar with the examples thereof sold under model designations 40880-15 or 40880-22 by the Ancra International, LLC identified above for use in restraining motorcycles and other recreational vehicles in the course of transport. Those skilled in the art will also appreciate that in actual use these tie-downs will be used to impose a certain preload on the suspension system of the restrained vehicle. The standard cam buckles are limited to the amount of force one can generate with one arm in a cramped space. Where somewhat higher preload forces are desired, the ratchet types are used; but they are not well suited for operation in cramped quarters. A simple cam type web tie-down system that will develop higher preload forces and improved operational convenience is provided in the inventive mechanism described below.

By reference to FIGS. 2A, 2B and 2C, it will be seen that the clamping levels obtainable in the foregoing cam buckle assembly can be even further improved by modifying its unitary frame to serve as a part of a secured pulley arrangement, thereby obtaining the higher preload restraint force levels that are required in the transport of heavier and more complex motorcycles or recreational vehicles. Like numbered parts operating in a like manner to that previously described, the inventively modified cam buckle assembly generally designated by the numeral 10 once again includes a unitary frame 11 in the form of a C-sectioned channel piece generally like the unitary frame UF in FIG. 1.

In a manner similar to the prior cam buckle, a unitary frame 11 is similarly defined by a lower surface BS bordered on either side by sidewalls WS1 and WS2. A bridging pin PP then extends across the sidewalls WS1 and WS2 to support the primary pulley.

As pulling tension is applied to the free end of a strap, the web will move along the inside of the base clamp frame; the primary pulley will turn the web back to pass under the locking cam of web buckle. In the application of the tie-downs, the manual force is applied at the free end FE of strap ST to overcome the opposing load from the compression of the suspension system of the transported vehicle. As the free end FE of the web is drawn out to increase the preload force, the web tension is resolved in part as a friction shear force on the locking cam. As the manual force MF is increased, the turning moment imposed on cam CP also increases to a point where the lever arm of the cam-lock is depressed downward deflecting the web spanning the distance between the primary pulley PP and the cam CP. When the manual force on the free end is stopped, the frictional turning moment on the cam is ended and the tension in the web span lifts the end of the lever arm of locking cam. As the cam rotates, the teeth of the cam engage the web and the clamp is locked tight by the web tension. The locked cam buckle can only be released by manually pressing the cam lever LE.

As can be seen, this inventive design of the web clamp, eliminates the requirement for the torsion spring to initiate the closing of the web clamp.

In the inventive buckle, a bridging post 18 is mounted across frame 11 to provide a post for an interlock cam adjacent to the cam CP. After the CP cam engages and locks onto the web, the CP cam is drawn tight by the web tension. The locking cam can then be rotated by one's thumb to tighten down on the nose of the CP cam, and thereby lock the CP cam. The CP cam actuating lever cannot be depressed until the locking cam is rotated back to disengage from the CP. This interlocking cam would prevent any accidental release of web clamp.

As noted in FIGS. 5 and 6 this inventive buckle accommodates multiple load lines so as to increase the preload capacity of the tie-down.

It will be appreciated that the foregoing arrangement provides the added security by the increased load capacity of the multi-load path web, and the extra security of the described web hooks. As a result, an inexpensive and rugged mechanism is provided that is widely useful in various applications.

The prior integral hook design would be suitable for many tie-down applications. However, for those applications requiring use of soft hooks, and or applications in cramped quarters, the end attachment type of web hooks depicted in FIGS. 3 and 4 is recommended. Soft hooks are now a standard means of attaching web tie-downs to modern street motorcycles.

FIGS. 3 and 4 show a hook design specifically for use with soft hooks that can be incorporated onto a force multiplying web clamp and used in the associated opposite hook end of web tie-down. This hook design can be part of the pivoting hook assembly to allow multiple load line for a force multiplication of the preload force capability of the tie-down. One such design would be a hook of rectangular cross section with one side open with a narrow gap or slit. The base of this hook opposite the gap would have a center pivot post. That narrow slit hook would attach to either the closed end of frame of the web buckle, or could be attached to a U-shaped frame that would support a post for pulley or web line termination. The dimensions of this hook would be specific in length, width, and gap opening to accept the specified soft hook loop. The soft hook would be cinched to the transported vehicle and also used to attach to cargo rings or cleats in the transporting truck or trailer.

The preferred web cam buckle assembly has the end of frame proximate the first turning roller closed out by a vertical wall connection between the opposing walls. This close out wall contains a center hole as a pivot mount for alternate end web hook designs.

The end attachment web hook apparatus is basically rectangular in shape, with one wall having a centerline gap sized to allow a sideways insertion of a portion of a closed strap web loop of specific width and thickness. Opposite the web gap is a centerline port to support a pivot post to attach this hook to the frame of the web buckle.

The end attachment web hook apparatus is attached to a center port of a U-shaped pulley frame to serve as a pivoting multiple line web hook assembly.

An adjusting plate attachment for the frame, shown in FIGS. 7A and 7B, allows the described web clamp to adjust to a wider range of web thickness materials.

Obviously many modifications and variations of the instant invention can be effected without departing from the spirit of the teaching herein. It is therefore intended that the scope of the invention be determined solely by the claims appended hereto. 

I claim:
 1. A cam buckle assembly configured as a frame having an elongated bottom surface, a pair of side surfaces along the edges of the bottom surface, a locking cam that has a cantilevered operating lever that is pivotally mounted in the frame, and a flexible strap aligned for capture between the locking cam and the bottom surface, the improvement comprising: a first turning roller mounted for rotation in said frame proximate the free end of said release lever.
 2. The assembly according to claim 1 where the dimensions and location of said first turning roller route the strap to a location passing immediately beneath the end of the operating lever.
 3. The assembly according to claim 2 where the tension resulting from a force applied to the free end of the strap initiates a closing movement of the operating lever of the locking cam.
 4. The assembly according to claim 3 where closing rotation of the operating lever results in engaging teeth of a locking cam to the strap, where tension rotates the clamp to be fully closed and locked.
 5. The assembly according to claim 1, further comprising a post for a second turning roller at an opposite end of the frame mounted for rotation in said frame.
 6. The assembly according to claim 1 further comprising an interlock cam adjacent to the clamping cam and that can be rotated to provide a positive lock to prevent release of the web clamp.
 7. The assembly according to claim 2, wherein one end of a side of said frame proximate said first turning roller forms a hook.
 8. The assembly according to claim 7 further comprising a latch on said hook for selectively closing said hook.
 9. The assembly according to claim 5, where said post provides a termination of a return web from a fixed end pulley.
 10. The assembly according to claim 5 where said post supports said second turning roller for further force magnification.
 11. The assembly according to claim 1 having the end of said frame proximate the first turning roller closed out by a vertical wall connection between the side surfaces and having a center hole as a pivot mount.
 12. The assembly recited in claim 11 further comprising an end attachment web hook apparatus that is rectangular in shape, with a forward wall having an opening path sized to allow a sideways insertion of a portion of a closed strap web loop of specific width and thickness, said web hook apparatus having a centerline port to support a pivot post to attach to said center hole pivot mount of the frame.
 13. The assembly recited in claim 11 further comprising an end attachment web hook apparatus attached to said center port of said frame to serve as a pivoting multiple line web hook assembly.
 14. The assembly recited in claim 1 further comprising an adjusting plate attachment for said frame to allow adjustment to different strap thicknesses. 